Virginia Gov. John N. Dalton today accepted the resignation of yet another member of the state's powerful highway commission, the third commissioner in four months to step down because of violations of the state's conflict-of-interest law.

H. Delmer Robinson Jr., an influential Winchester businessman and Republican city councilman whom Dalton had appointed to the commission last year, said he was resigning because he is an officer and stockholder in two companies that did business with the state Department of Highways and Transportation while he was on the commission.

Dalton announced the resignation at a press conference where he again denounced the conflict-of-interest statute as too stringent and complex and accused the press of "harassing" and "bugging" Robinson into resigning. "I quite frankly urged him not to resign," said the governor.

Virginia law requires that any public official doing business with a state or local government agency give in advance a written disclosure of his financial interest to both the agency he works for and the agency he wishes to do business with. Robinson acknowledged today that he had not done so since becoming a highway commissioner.

While contending that the state money his companies have received totals less than $5,000 and denying he had any personal knowledge of the transactions, Robinson said in his resignation letter that "this does not excuse the fact that a conflict does and has existed for some time . . . . "

Robinson, who termed the disclosure section of the law "absolutely ridiculous," told the press conference he was not resigning because of what he termed "technical violations," but rather because of the possibility that one of the many businesses he is connected to might inadvertently violate the law in the future. "I felt a conflict could come from a source that I was not aware of," he said.

Highway department records show that two of Robinson's companies, Winchester Equipment Co., of which he is president, and Oil Heat & Burner Service Inc., of which he is vice president, have sold a total of $5,403 worth of spare parts for herbicide spraying machines and propane gas to the agency since Robinson joined the commission in July 1980. Robinson today put the amount at $4,588 and offered no explanation for the discrepancy.

Robinson said he had about a 10 percent interest in each of the companies and no knowledge of their day-to-day operations. He said he only learned of the transactions after being informed of them earlier this week by highway officials.

Dalton said the department discovered the conflict after a Washington Post reporter made a request under the state's Freedom of Information Act for a listing of all such transactions. The matter was then turned over to the state attorney general's office, which the governor said advised him earlier this week that the violation was not "willful."

The governor said that Deputy Attorney General Walter A. McFarlane had recommended to him that Robinson could stay on as commissioner. Benjamin Ragsdale, spokesman for the attorney general, said the office would have no comment on its role in Robinson's resignation.

Dalton accused reporters of harassing Robinson and other highway commissioners by making requests for their financial disclosure statements, which state law requires them to file with the attorney general, and by calling them on the phone. "Somebody keeps calling them and bugging them about it," said the governor, who said he had been told other commissioners are worried that they may be violating the law -- a subject comes up "at every meeting of the highway commission."

Robinson himself denied he had been harassed, but said of the repeated requests for his disclosure statement by reporters and by a legislative commission studying the department, "Everybody gives you the feeling you're involved in something irregular and dishonest."

The governor added that "Mr. Robinson has decided that the hassle he has got to go through to serve for $50 a day the salary paid highway commissioners on the days the panel meets . . . is not worth it."

Both Robinson and the governor, who as a state legislator had cosponsored the conflict law in 1970, said revisions were needed in the law's provision that requires advance disclosure of transactions with public agencies. Both contended the law should not require a citizen member of a public body to disclose in advance dealings with agencies other than the one on which he serves -- a change that would not have affected Robinson's acknowledged conflict.

They also suggested that the law should not require disclosure in cases where the transactions resulted from competitive bidding. Highway department records indicate the propane purchases from Robinson's firm were made after competitive bidding while the spare parts were not. The parts were bought for sprayers that had been purchased by competitive bid from Winchester Equipment in 1979 -- a year before Robinson joined the commission.

Dalton said the present law could force hundreds of successful businessmen off state boards and commissions and was making it difficult to recruit new members. "I don't think any of us when this thing was passed had any conception of how far this thing would be carried," he said, promising to recommend revisions in his final message to the General Assembly next month.

Robinson's departure from the 10-member commission is the third in recent months. Dalton ousted Northern Virginia commissioner William B. Wrench in September after The Washington Post revealed that Wrench had voted to reroute a major Fairfax County roadway near three parcels of land he owned and had failed to disclose all his land holdings to the commission. Three weeks later, the governor forced Tidewater Commissioner T. Ray Hassell III off the panel because Hassell failed to disclose that his engineering and surveying firm had accepted contracts from other state agencies.

The Republican governor, who leaves office Jan. 16, said he did not know whether he would attempt to apppoint a successor to Robinson. Dalton has named two Republicans to succeed Wrench and Hassell, but both nominees face strong opposition from Democratic legislators who contend the appointments should have been left to the incoming governor, Democrat Charles S. Robb.

Robb has agreed that the present conflict law needs to be more specific, but has not advocated the sweeping changes Dalton has urged. Common Cause of Virginia, a lobbying organization, and several legislators have challenged Dalton's view of the law and said the current controversy illustrates the need for a more stringent conflict statue.